Adjustment and stabilizer mechanism for dozer blade

Abstract

A mechanism for angling, pitching, and tilting a dozer blade utilized in a conventional bulldozer wherein the blade is pivotally connected by an angling frame to the forward ends of push arms. A tilt-pitch control assembly for the blade is provided including a pitch cylinder, a pitch-tilt cylinder, a torsion bar, and drag link connections. The pitch cylinder and pitch-tilt cylinder are each pivotally attached to the torsion bar by the drag link connections. If a load is applied against one side of the blade, the load is transmitted to the pitch cylinder or pitch-tilt cylinder closest to the loaded side of the blade thereby causing some movement of that cylinder. The cylinder which is under load transmits any movement through its respective drag link connection into a turning movement on the torsion bar. This turning movement on the torsion bar is, in turn, transmitted to the opposite side of the blade and to the unloaded cylinder which provides support to the loaded cylinder for counteracting any uneven or undistributed loads on the blade. The pitch-tilt cylinder includes opposed extensible piston rods for providing maximum blade tilt at all pitch positions of the blade. This overcomes the problem of having no tilt cylinder stroke available to tilt the blade when the blade is fully pitched forwardly or rearwardly. Thus, the present construction provides for maximum blade tilt at all pitch positions of the blade and a stabilizing arrangement to prevent the blade from following the path of least resistance when uneven loads are applied to the blade.

I claim: 
     
       1. In an earth-working machine having a frame, a pair of push arms pivotally secured at one of their ends to said frame, and a blade pivotally secured to the push arms at their other ends, a pair of lift cylinders pivotally interconnected between said frame and said blade, the improvement comprising: 
     
     
       a pitch-tilt control assembly for said blade including a pitch piston cylinder, a pitch-tilt piston cylinder, a torsion bar, and a pair of drag link connections, means for mounting said torsion bar to the backside of said blade, said torsion bar extending generally parallel to the backside of said blade and being rotatable about its longitudinal axis, said pitch piston cylinder being pivotally attached at one end to said torsion bar and pivotally attached at its opposite end to one of said push arms, said pitch-tilt piston cylinder being pivotally attached at one end to said torsion bar and pivotally attached at its other end to the other of said push arms, said pitch piston cylinder and said pitch-tilt piston cylinder being additionally pivotally attached to said torsion bar by said drag link connections whereby a load on one side of said blade being transmitted to the opposite side of said blade by said torsion bar and drag link connections for counteracting uneven loads on said blade and preventing said blade from following a path of least resistance when uneven loads are applied to said blade. 
     
     
       2. The earth-working machine as defined in claim 1 wherein each of said drag link connections includes a bracket fixed to said torsion bar, a drag link pivotally connected at one end to a lower depending end of said bracket and having its opposite end pivotally connected to a weldment extending from a respective piston cylinder. 
     
     
       3. The earth-working machine as defined in claim 1 wherein each of said drag link connections includes a bracket fixed to said torsion bar, a yoke-like link pivotally connected at one end to a lower depending end of said bracket and having an opposite bifurcated end pivotally attached to opposite sides of a respective piston cylinder. 
     
     
       4. The earth-working machine as defined in claim 1 wherein said pitch-tilt piston cylinder includes opposed extensible piston rods mounted within a housing having an interior seal for dividing said housing into a pair of opposed actuating chambers, a pitch control valve for supplying fluid pressure into one of said actuating chambers thereby extending one of said piston rods for providing pitching movement to said blade and a tilt control valve for supplying fluid pressure into the other of said actuating chambers thereby extending the other piston rod for providing tilting movement to said blade whereby said pitch-tilt piston cylinder provides a maximum amount of blade tilt movement for all pitch positions of said blade. 
     
     
       5. In an earth-working machine having a frame and a pair of push arms pivotally secured at one of their ends to said frame, the improvement comprising: a blade angling frame pivotally attached to the forward ends of said push arms and a blade pivotally mounted on the front of said angling frame for movement about a vertical axis, a pair of piston cylinders connected at one end to said angling frame and having their opposed ends connected to respective sides of said blade, one of said piston cylinders being extended while the other piston cylinder being retracted for angling said blade about said vertical axis;   a pitch-tilt control assembly for said blade including a pitch piston cylinder and a pitch-tilt piston cylinder, said pitch piston cylinder being pivotally attached at one end to said angling frame and pivotally attached at its opposite end to one of said push arms, said pitch-tilt piston cylinder being pivotally attached at one end to said angling frame and pivotally attached at its other end to the other of said push arms, and said pitch-tilt piston cylinder including opposed extensible piston rods mounted within a housing having an interior seal for dividing said housing into a pair of opposed actuating chambers, a pitch control valve for supplying fluid pressure into one of said actuating chambers thereby extending one of said piston rods for providing pitching movement to said blade, a tilt control valve for supplying fluid pressure into the other of said actuating chambers thereby extending the other of said piston rods for providing tilting movement to said blade whereby said pitch-tilt cylinder provides a maximum amount of blade tilt movement for all pitch positions of said blade; and   wherein said pitch-tilt control assembly further includes a torsion bar and a pair of drag link connections, means for mounting said torsion bar to the backside of said angling frame, said torsion bar extending generally parallel to the backside of said angling frame and being rotatable about its longitudinal axis, said pitch piston cylinder and said pitch-tilt piston cylinder being pivotally attached to said torsion bar by said drag link connections whereby a load on one side of said blade being transmitted to the opposite side of said blade by said torsion bar and drag link connections for counteracting uneven loads on said blade and preventing said blade from following a path of least resistance when uneven loads are applied to said blade.